167 research outputs found

    A low-pass filter with automatic frequency tuning for a bluetooth receiver

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    A third-order Gm-C Chebyshev low-pass filter with high linearity and automatic frequency programmability has been designed. The filter is intended to be used as a channel-select filter for a zero-IF Bluetooth receiver. The frequency tuning scheme is simpler and has more relaxed specifications than conventional ones. The filter bandwidth is 0.5 MHz and the overall scheme dissipates 1.1 mA from a 1.8-V supply. The third-order intermodulation (IM3) distortion of the filter for a 1Vpp two-tone signal centered at 350 kHz is -67dB.Ministerio de Ciencia y Tecnología TEC2007-67460-C03-02

    Design of a band-pass sigma-delta modulator with reduced number of opamps

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    This paper is intended to compare the performance of a Band-Pass converter structure and its Low-Pass prototype 2nd order Sigma-Delta Analog to Digital converter. For this purpose Matlab simulations for the 4th order Band-Pass converter have been performed and its power consumption calculated when using the equivalent Op-Amp used m the Low-Pass modulator. First of all will be described the method used to calculate the transfer function and, thus the structure of the Band-Pass structure to be tested. After a band-pass transfer function has been obtained it is implemented using reduced number of opamps. This topology is compared to the existing ones and a system level simulation and characterisation is performed. Finally, jitter limitations are studied. Transistor level simulations using Spectre have been done in order to validate MATLAB simulations prior to layout design

    Effect of band-filling and structural distortions on the Curie temperature of Fe-Mo double perovkites

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    By means of high resolution neutron powder diffraction at low temperature we have characterized the structural details of LaxSr2xFeMoO6\rm La_{x}Sr_{2-x}FeMoO_6 (0x0.50\leq {\rm x}\leq 0.5) and CaxSr2xFeMoO6\rm Ca_{x}Sr_{2-x}FeMoO_6 (0x0.60\leq {\rm x}\leq 0.6) series of compounds. This study reveals a similar variation of the mean bond-angle \FeOMo in both series. In contrast, the mean bond-distance \FeMoO\ increases with La but not with Ca substitution. Both series also present a different evolution of the Curie temperature (TCT_C), which raises in the La series and slightly decreases in the Ca one. We thus conclude that the enhancement of TCT_C in the La series is due to the electron filling of the conduction band and a concomitant rising of the density of states at the Fermi level.Comment: Revtex, 4 Journal pages, 2 figures, 1 tabl

    The jigsaw of PRRSV virulence

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    Porcine reproductive and respiratory syndrome virus (PRRSV) is the causative agent of the, probably, most economically important disease for the pig industry worldwide. This disease, characterised by producing reproductive failure in sows and respiratory problems in growing pigs, appeared in the late 1980s in the United States and Canada. Since its appearance, strains capable of producing higher mortality rates as well as greater severity in clinical signs and lesions than classical strains have been identified. However, since the first reports of these “virulent” PRRSV outbreaks, no homogeneity and consensus in their description have been established. Moreover, to the authors’ knowledge, there is no published information related to the criteria that a PRRSV strain should fulfil to be considered as a “virulent” strain. In this review, we revise the terminology used and gather the information related to the main characteristics and differences in clinical signs, lesions, viral replication and tropism as well as immunological parameters between virulent and classical PRRSV strains and propose a first approximation to the criteria to define a virulent PRRSV strain

    Activation of T-bet, FOXP3, and EOMES in Target Organs From Piglets Infected With the Virulent PRRSV-1 Lena Strain

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    Transcription factors (TFs) modulate genes involved in cell-type-specific proliferative and migratory properties, metabolic features, and effector functions. Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important pathogen agents in the porcine industry; however, TFs have been poorly studied during the course of this disease. Therefore, we aimed to evaluate the expressions of the TFs T-bet, GATA3, FOXP3, and Eomesodermin (EOMES) in target organs (the lung, tracheobronchial lymph node, and thymus) and those of different effector cytokines (IFNG, TNFA, and IL10) and the Fas ligand (FASL) during the early phase of infection with PRRSV-1 strains of different virulence. Target organs from mock-, virulent Lena-, and low virulent 3249-infected animals humanely euthanized at 1, 3, 6, 8, and 13 days post-infection (dpi) were collected to analyze the PRRSV viral load, histopathological lesions, and relative quantification through reverse transcription quantitative PCR (RT-qPCR) of the TFs and cytokines. Animals belonging to both infected groups, but mainly those infected with the virulent Lena strain, showed upregulation of the TFs T-bet, EOMES, and FOXP3, together with an increase of the cytokine IFN-g in target organs at the end of the study (approximately 2 weeks post-infection). These results are suggestive of a stronger polarization to Th1 cells and regulatory T cells (Tregs), but also CD4+ cytotoxic T lymphocytes (CTLs), effector CD8+ T cells, and gdT cells in virulent PRRSV-1-infected animals; however, their biological functionality should be the object of further studies

    Crossover in the nature of the metallic phases in the perovskite-type RNiO_3

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    We have measured the photoemission spectra of Nd1x_{1-x}Smx_{x}NiO3_{3}, where the metal-insulator transition and the N\'{e}el ordering occur at the same temperature for x0.4x \lesssim 0.4 and the metal-insulator transition temperature (TMIT_{MI}) is higher than the N\'{e}el temperature for x0.4x \gtrsim 0.4. For x0.4x \le 0.4, the spectral intensity at the Fermi level is high in the metallic phase above TMIT_{MI} and gradually decreases with cooling in the insulating phase below TMIT_{MI} while for x>0.4x > 0.4 it shows a pseudogap-like behavior above TMIT_{MI} and further diminishes below TMIT_{MI}. The results clearly establish that there is a sharp change in the nature of the electronic correlations in the middle (x0.4x \sim 0.4) of the metallic phase of the RRNiO3_3 system.Comment: 4 pages, 4 figure, submitted to Phys. Rev.

    Activation of pro- and anti-inflammatory responses in lung tissue injury during the acute phase of PRRSV-1 infection with the virulent strain Lena

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    Porcine reproductive and respiratory syndrome virus (PRRSV) plays a key role in porcine respiratory disease complex modulating the host immune response and favouring secondary bacterial infections. Pulmonary alveolar macrophages (PAMs) are the main cells supporting PRRSV replication, with CD163 as the essential receptor for viral infection. Although interstitial pneumonia is by far the representative lung lesion, suppurative bronchopneumonia is described for PRRSV virulent strains. This research explores the role of several immune markers potentially involved in the regulation of the inflammatory response and sensitisation of lung to secondary bacterial infections by PRRSV-1 strains of different virulence. Conventional pigs were intranasally inoculated with the virulent subtype 3 Lena strain or the low virulent subtype 1 3249 strain and euthanised at 1, 3, 6 and 8 dpi. Lena-infected pigs exhibited more severe clinical signs, macroscopic lung score and viraemia associated with an increase of IL-6 and IFN-γ in sera compared to 3249-infected pigs. Extensive areas of lung consolidation corresponding with suppurative bronchopneumonia were observed in Lena-infected pigs. Lung viral load and PRRSV-N-protein+ cells were always higher in Lena-infected animals. PRRSV-N-protein+ cells were linked to a marked drop of CD163+ macrophages. The number of CD14+ and iNOS+ cells gradually increased along PRRSV-1 infection, being more evident in Lena-infected pigs. The frequency of CD200R1+ and FoxP3+ cells peaked late in both PRRSV-1 strains, with a strong correlation between CD200R1+ cells and lung injury in Lena-infected pigs. These results highlight the role of molecules involved in the earlier and higher extent of lung lesions in piglets infected with the virulent Lena strain, pointing out the activation of routes potentially involved in the restraint of the local inflammatory response.info:eu-repo/semantics/acceptedVersio

    Volcanic eruption of Cumbre Vieja, La Palma, Spain: A first insight to the particulate matter injected in the troposphere

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    The volcanic eruption of Cumbre Vieja (La Palma Island, Spain), started on 19 September 2021 and was declared terminated on 25 December 2021. A complete set of aerosol measurements were deployed around the volcano within the first month of the eruptive activity. This paper describes the results of the observations made at Tazacorte on the west bank of the island where a polarized micro-pulse lidar was deployed. The analyzed two-and-a-half months (16 October–31 December) reveal that the peak height of the lowermost and strongest volcanic plume did not exceed 3 km (the mean of the hourly values is 1.43 ± 0.45 km over the whole period) and was highly variable. The peak height of the lowermost volcanic plume steadily increased until week 11 after the eruption started (and 3 weeks before its end) and started decreasing afterward. The ash mass concentration was assessed with a method based on the polarization capability of the instrument. Two days with a high ash load were selected: The ash backscatter coefficient, aerosol optical depth, and the volume and particle depolarization ratios were, respectively, 3.6 (2.4) Mm−1sr−1, 0.52 (0.19), 0.13 (0.07) and 0.23 (0.13) on 18 October (15 November). Considering the limitation of current remote sensing techniques to detect large-to-giant particles, the ash mass concentration on the day with the highest ash load (18 October) was estimated to have peaked in the range of 800–3200 μg m−3 in the lowermost layer below 2.5 km.This research was funded by the Spanish Ministry of Science and Innovation (PID2020- 118793GA-I00, PID2019-104205GB-C21, EQC2018-004686-P and PID2019-103886RB-I00), the H2020 program from the European Union (GA no. 19ENV04, 654109, 778349, 871115 and 101008004), and the Unit of Excellence “María de Maeztu” (MDM-2017-0737) financed by the Spanish State Research Agency (AEI). The authors wish to thank ACTRIS, AEROSPAIN and Junta de Castilla y León (ref: VA227P20) for supporting the calibration of the AERONET sun photometers used in this publication, and also to Ayuntamiento de Tazacorte, Ayuntamiento de Fuencaliente and Cabildo Insular de La Palma for their help in terms of infrastructure and logistics. M.-Á.L.-C. and C.V.C.-P. are supported by the INTA predoctoral contract program. E.J.W. is funded by the NASA Radiation Sciences Program and Earth Observing System.Peer ReviewedArticle signat per 16 autors/es: Michaël Sicard (1,2), Carmen Córdoba-Jabonero (3), Africa Barreto (4), Ellsworth J. Welton (5), Cristina Gil-Díaz (1),Clara V. Carvajal-Pérez (3), Adolfo Comerón (1), Omaira García (4), Rosa García (6), María-Ángeles López-Cayuela (3),Constantino Muñoz-Porcar (1), Natalia Prats (4), Ramón Ramos (4), Alejandro Rodríguez-Gómez (1), Carlos Toledano (7), Carlos Torres (4) // (1) CommSensLab, Department of Signal Theory and Communications, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain; (2) Ciències i Tecnologies de l’Espai-Centre de Recerca de l’Aeronàutica i de l’Espai/Institut d’Estudis Espacials de Catalunya (CTE-CRAE/IEEC), Universitat Politècnica de Catalunya, 08034 Barcelona, Spain; (3) Atmospheric Research and Instrumentation Branch, Instituto Nacional de Técnica Aeroespacial (INTA), 28850 Torrejon de Ardoz, Spain; (4) Izaña Atmospheric Research Center, State Meteorological Agency of Spain (AEMET), 38001 Santa Cruz de Tenerife, Spain: (5) Code 612, Goddard Space Flight Center, National Aeronautics and Space Administration, Greenbelt, MD 20771, USA; (6) TRAGSATEC, 28006 Madrid, Spain; (7) Group of Atmospheric Optics, Universidad de Valladolid, 47011 Valladolid, SpainPostprint (published version

    Dental Caries Prevalence and Tooth Loss in Chilean Adult Population: First National Dental Examination Survey

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    The purpose of this study was to assess the prevalence of dental caries, tooth loss, and risk factors among adult population of Chile. Furthermore, age, gender, and behavioural specific differences in caries prevalence and tooth loss were examined. A national stratified multistage probabilistic sample design in two-age cohorts was applied to the Chilean population. A sample of 1553 adults, comprising 1088 individuals aged 35–44 and 465 senior individuals aged 65–74, were examined. The DMFT was evaluated following WHO recommendations using diagnostic criteria of caries lesions into dentin. The data were analyzed by univariate and multivariate models using logistic regression analyses. Results showed a mean DMFT of 15.06 in the 35–44-year-old group and of 21.57 in the 65–74 group. Factors related to tooth loss in the 35–44 group through univariate logistic regression were depression (OR 1.9 CI 95% 1.26–2.85), education level <12 years (OR 2.24 CI 95% 1.31–3.73), personal income (OR 1.51 CI 95% 1.04–2.19), and familiar income (OR 2.05 CI 95% 1.34–3.13), and through multivariate logistic regression in the same age group were depression (OR 1.93 CI 95% 1.24–3.0), education level <12 years (OR 1.94 CI 95% 1.2–3.14), and familiar income (OR 1.71 CI 95% 1.09–2.68). Factors related to tooth loss in the 65–74-year-old group through univariate logistic regression were education level <12 years (OR 2.54 CI 95% 1.3–4.96) and personal income (OR 1.66 CI 95% 1.05–2.63), and for multivariate logistic regression in the same age group, it was education level <12 years (OR 2.51 CI 95% 1.21–5.18). In conclusion, adult population in Chile showed a high prevalence of dental caries and tooth loss, as age, education level, personal and familiar incomes, and depression are being the main risk factors
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